Hydraulic control device

ABSTRACT

An hydraulic control device which can be used particularly for the control of a winch driven by an hydraulic motor, having two slide valve distributors, whose slide valves are subjected to the action of a spring to position them in a rest position. The slide valves are each capable of occupying two positions and are coupled to a single operating lever. A first distributor situated in a duct ensures the permanent opening of the duct in the rest position while the second distributor situated in series with the first, is of the reversing device type and places the first distributor in selective communicating with two other ducts connected respectively to a source of fluid under pressure and to a discharge reservoir. The rest position of the second distributor corresponds to the connection of the first with the reservoir. The slide valve of the first distributor is coupled on the one hand to a single acting ram supplied by the fluid conveyed between the first and the second distributor.

United States Patent Praddaude [451 Apr. 18, 1972 [54] HYDRAULIC CONTROLDEVICE 3,253,613 5/1966 Richolt ..137/625.69 3,274,779 9/1966 Klein..9l/420 [72] praddaude 3,426,648 2/1969 Fehlings ..91/420 [73]Assignee: Societe Anonyme Poclain, Le-Plessis-Bel- Primary Examiner-PaulE. Maslousky leville, Oise, France Attorney-Mason, Fenwick & Lawrence[22] Filed: Feb. 7, 1969 [57] ABSTRACT [21] Appl 797594 An hydrauliccontrol device which can be used particularly for the control of a winchdriven by an hydraulic motor, having [30] Foreign Application PriorityData two slidevalve distributors, whose slide valves are subjected tothe action of a spring to position them in a rest position. The Feb. 7,France slide valves are each capable of occupying v0 positions and arecoupled to a single operating lever. A first distributor situ- [52]11.8.0 ..60/1,9l/42(l)53/1g262, med in a duct ensures thepermanemopening ofthe duct in the rest position while the seconddistributor situated in series 22 ifi 'ms 55 148: with the first, is ofthe reversing device type and places the 1 1e 0 91/146. 1372625 60/1first distributor in selective communicating with two other ductsconnected respectively to a source of fluid under pressure and to adischarge reservoir. The rest position of the [56] References cuedsecond distributor corresponds to the connection of the first UNITEDSTATES PATENTS with the reservoir. The slide yalve olt" the firstdistributor is coupled on the one hand to a single acting ram supphed bythe 1; 6 g fluid conveyed between the first and the second distributor.or 1115 2,964,908 12/1960 Pomper et al ..91/446 12 Claims, 2 DrawingFigures PATENTEUAP 18 I972 INVENTOR Piazza APQAbu-AuoE wasg'u A- 7ATTORNEYS It is known that certain hydraulic motors and in particularwinch motors are subjected permanently to a couple in a definite senseby reason for example of the existence of a load at the end of the winchcable. Thus in operation four phases are produced which can besummarized as follows:

1. Stopping and, possibly, locking.

2. Controlled rotation in a first sense (lifting).

3. Controlled rotation in the second sense (controlled lowering).

4. Free rotation in the second sense (free lowering).

Hydraulic distributors have already been thought of having fourpositions ensuring these four phases of operation. However, in theposition of free lowering" which is often called the float position, itis necessary to provide a speed limiter, constituted by a calibratedvalve or preferably by a valve driven by the pressure of the fluiddelivered by the pump. At any rate, in these known arrangements when themotor is in the stop position the fluid delivered by the pump must passthrough the speed limiter valve: thus a wastage of power results.

Thus the present invention has for its object a hydraulic control devicefor this kind of motor, or more generally receiver, particularlyapplicable to the control of winch motors.

According to the invention it comprises two slide valve distributors,the slide valves of which subjected to the action of a spring restoringthem to a position, called the rest position, are each capable ofoccupying two positions and are coupled to a single operating lever. Afirst distributor situated in one duct ensures the permanent opening ofthe said duct in the rest position and, of course, its closing in theother position.

The second distributor of the reversing device type, is in series withthe first distributor and places it in selective communication with twoother ducts connected respectively to a source of fluid under pressureand to a reservoir.

Finally, the slide valve of the first distributor is coupled to a singleacting ram supplied by the fluid conveyed by the duct connecting thefirst distributor to the second.

When the control device is used for the control of an hydraulicreceiver, motor or ram, the movement of which can be effected in twoopposite senses, the two supply conduits of the receiver are arranged inparallel on the first distributor.

As will be shown further on, these arrangements make available a controlhaving four positions, one phase in the operation of the receivercorresponding to a movement which is effected under the action of anexternal force.

Furthermore the invention will be better understood and certain othercharacteristics will become apparent in the course of the description ofone embodiment given solely by way of example with reference to theaccompanying drawing in which:

FM. 11 illustrates a diagrammatic view of a device in accordance withthe invention;

Fit 2 illustrates a diagram of the connections of the device in the caseof its application to the control of a winch motor, the different partsbeing in the position corresponding to the stop position of the motor.

Referring to the drawing, it can be seen that the device comprisesessentially two slide valve distributors l and 2 arranged in series in aduct 3. The slide valves lie and 2a of these distributors are coupled toa control lever t through a pivot point do and through a guide rod hingedb. On the other hand these slide valves, capable of occupying twopositions, are subjected to the action of springs 5 which restore theminto their rest position and which is that illustrated in the drawing infull lines. However, the slide valve la is furthermore shaped at itsfree end to form a piston operating in a cylinder ti, the assembly thusconstituting a single acting hydraulic pilot ram acting against thecorresponding spring 5 and supplied through a duct 7 connected to theduct 3 between the two distributors.

The distributor 1 permits selective closing of the duct 3 but, in itsrest position, ensures the permanent opening of this duct. On the otherhand, the distributor 2 is of the reversing device type and permitsselective communication between the duct 3 and one of the two ducts 8and 9 which lead respectively to a source of fluid under pressure, forexample a pump ll) which can be seen in FIG. 2, and to a dischargereservoir ill. in the rest position of the distributor 2, the duct 3 isin communication with the duct 9 and the reservoir 11. Referring moreparticularly to FIG. 2, it can be seen that the application of a devicein accordance with the invention to the control of an hydraulic winchmotor 12, or more generally of a receiver, the

"supply ducts 13 and 14 are connected on the one hand to the duct 3 andon the other hand to the: distributor ll. However, it must be noted thatthe duct 13 whose fluid supply under pres sure corresponds to therotation of the motor in the sense of lowering of the load, is connectedbetween the two distributors l and 2.

Beyond the distributor l the duct 3 is connected to the duct 8 betweenthe pump 10 and the distributor 2. Furthermore a non-return valve 15 isarranged in this portion of the duct 3 and only allows the passage offluid coming from the pump.

Finally a tapping 16 is connected to the duct 3, after the distributor1, this tapping being connected to the reservoir duct 9. It contains apilot valve 17 controlled in a quite normal fashion, by fluid pressureat a predetermined location. In this case, the duct 18 forcontrollingthis valve 17 is connected to the duct 3 between the distributors l and2. The fluid can only pass the valve 17 towards the reservoir llll ifthe pressure in the duct 18 is suti'icient.

In the operation of the embodiment of the invention illustrated in FIGS.1 and 2, when the control lever Al is in the position as illustrated bythe solid lines in FIG. 1, so that distributor 1 is in the open positionand distributor 2 communicates fluid line 3 with fluid discharge line 9as illustrated in FIG. 2, fluid under pressure will flow from the pumpll) through fluid line 8, the portion of fluid line 3 interconnectingfluid line ti and distributor 2 which includes one-way valve 115,distribu tors 1 and 2, and fluid discharge line 9, into the reservoirill. Under such conditions, fluid under pressure will be bypassedthrough the distributor 1 and will not be supplied to the fluid motor 12to operate the motor in either forward or reverse drive. In addition,the valve 17 will remain closed, and the winch operated by the fluidmotor 12 will be inactive.

When it is desired to operate the winch to lift a load, control lever 4is pivoted about the pivot point 4b to the position A as illustrated inFIG. 1, whereupon distributor 1 closes and distributor 2 continues tocommunicate the portion of fluid line 3 interconnecting distributors 1and 2 with fluid discharge line 9. Under such circumstances, pump 10supplies fluid under pressure through fluid line 8, the portion of line3 interconnecting fluid line 8 and distributor I, and fluid line lid tooperate fluid motor 12 in the reverse direction thus causing the winchto rotate and provide a lifting action. Fluid is returned to reservoir11 from fluid motor 12 through fluid line 13, the portion of fluid line3 interconnecting distributors l and 2, distributor 2 and fluiddischarge line 9. During this phase of operation of the control system,the valve 17 remains closed.

If then it is desired to utilize the winch for lowering a load, controllever 4 is moved to the position B as illustrated in FIG. 1 so thatdistributor 1 is in the closed position and distributor 2 functions tocommunicate fluid line 8 with the portion of line 3 interconnectingdistributors 1 and 2. Under these conditions, pump 10 will supply fluidunder pressure through fluid line 8, distributor 2, the portion of fluidline 3 interconnecting distributors l and 2, and fluid line 113 tofluid-motor 12 to operate the motor in forward drive. When fluid isapplied to fluid line 13, fluid under pressure will be supplied to theend of distributor 1 through the fluid line 7 to urge the sliding spoolof distributor 1 in the closed position. A predetermined amount ofpressure in fluid line 3 between distributors l and 2 also will apply asufficient pressure to line 18 to open valve 17'.

The opening of valve 17 permits fluid to return from fluid motor 12through fluid line 14, a portion of fluid line 3 interconnecting fluidlines 14 and 16, and fluid line 16 to the reservoir 11. In this phase ofoperation, the speed of the fluid motor 12 can be controlled byregulating the distributor 2. The pressure in fluid line 3 betweendistributors l and 2 will vary the pressure applied to valve 17 and thusregulate the return of fluid from the motor 12. The valve 17 thus mayfunction as a speed regulator when the control system is operated tolower a load.

Finally, when it is desired to freely lower the winch load, the controllever 4 is moved to position C as illustrated in FIG. 1 to opendistributor 1 and cause distributor 2 to communicate fluid line 8 withthe portion of fluid line 3 interconnecting distributors 1 and 2. Undersuch conditions, fluid under pressure will be supplied to the fluid line18 through distributor 2 and the portion of line 3 interconnectingdistributors 1 and 2, to open valve 17, thus permitting fluid underpressure to circu late through fluid line 8, the portion of fluid line 3including one-way valve and fluid line 16, to reservoir 11.Simultaneously, fluid in the fluid motor 12 will be caused to circulatefreely through fluid line 13, the fluid motor 12, fluid line 14 and thatportion of fluid line 3 including the distributor 1.

From the above description of the operation of the embodimentillustrated in FIGS. 1 and 2, it will be appreciated that by simplemanipulation of the control lever 4 into the various positions asillustrated in FIG. 1, the fluid motor 12 may be operated to hold, lift,lower at a controlled rate or lower at a freely falling rate, aparticular winch load.

It must be noted that the control in accordance with the inventionprovides a high degree of safety. In effect the freedom given to themotor or more generally to the receiver, to be freely moved under theaction of an external force is subordinate to the exercise of aconsiderable force on the part of the operator at the lever 4 toovercome the force of the pressure on the slide valve 1a.

Of course the invention is not limited to the embodiment described andillustrated but on the contrary covers all variants and in particularall uses whatever may be the type of receiver under control.

Iclaim:

1. A fluid control system comprising a fluid motor, a first fluid lineincluding first and second valves disposed in series, said first valvebeing movable selectively into open and close positions, said secondvalve being operable to selectively communicate said first fluid linewith a source of fluid under pressure and a fluid discharge, a portionof said first fluid line connected only to said first valve beingcommunicable with said source of fluid under pressure, and second andthird fluid lines connected to said first fluid line and operativelyconnected to said fluid motor whereby said fluid motor is connected inparallel relative to said first valve.

2. A fluid control system according to claim 1 wherein said first valvenormally is in the open position and said second valve normallycommunicates said first fluid line with said fluid discharge.

3. A fluid control system according to claim 1 wherein said first valveis urged into the closed position responsive to a predetermined pressurein said second fluid line.

4. A fluid control system according to claim 1 including actuating meansoperatively connected to said fiist and second valves.

5. A fluid control system according to claim 1 wherein said first valveconsists of a slide valve having a movable spool, said spool beingmovable responsive to a predetermined pressure in said second fluid lineto urge said first valve in the closed position.

6. A fluid control system according to claim 1 wherein said first andsecond valves consist of slide valves having movable spools providedwith actuating rods, and including a control lever pivotally connectedto the actuating rods of said first and second valves. I

7. A fluid control system according to claim 6 wherein said pivotalconnections are spaced along the length of said control lever.

8. A fluid control system according to claim 1 including a one-way valvedisposed in said first fluid line in series between said first valve andsaid fluid discharge.

9. A fluid control system according to claim 1 including a fourth fluidline interconnecting said first fluid line between said first valve andsaid source of fluid under pressure, and said fluid discharge, saidfourth fluid line including a normally closed valve operable to openresponsive to a predetermined pressure in said first fluid line betweensaid first and second valves.

10. A fluid control system according to claim 1 including a one-wayvalve disposed in said first fluid line in series between said firstvalve and said source of fluid under pressure, and a fourth fluid lineinterconnecting said first fluid line between said first valve and saidone-way valve, and said fluid discharge, said fourth fluid lineincluding a normally closed valve operable to open responsive to apredetermined pressure in said first fluid line between said first andsecond valves.

1 1. A fluid control system according to claim 1 wherein said first andsecond valves consist of slide valves having movable spools providedwith actuating rods, and including a control lever pivotally connectedat spaced points along its length to said actuating rods, a one-wayvalve disposed in said first fluid line in series between said firstvalve and said source of fluid under pressure, and a fourth fluid lineinterconnecting said first fluid line between said first valve and saidone-way valve, and said fluid discharge, said fourth fluid lineincluding a normally closed valve operable to open responsive to apredetermined pressure in said first fluid line between said first andsecond valves.

12. A fluid control system according to claim 11 wherein said firstvalve is urged into the closed position responsive to a predeterminedpressure in said second fluid line.

1. A fluid control system comprising a fluid motor, a first fluid line including first and second valves disposed in series, said first valve being movable selectively into open and close positions, said second valve being operable to selectively communicate said first fluid line with a source of fluid under pressure and a fluid discharge, a portion of said first fluid line connected only to said first valve being communicable with said source of fluid under pressure, and second and third fluid lines connected to said first fluid line and operatively connected to said fluid motor whereby said fluid motor is connected in parallel relative to said first valve.
 2. A fluid control system according to claim 1 wherein said first valve normally is in the open position and said second valve normally communicates said first fluid line with said fluid discharge.
 3. A fluid control system according to claim 1 wherein said first valve is urged into the closed position responsive to a predetermined pressure in said second fluid line.
 4. A fluid control system according to claim 1 including actuating means operatively connected to said first and second valves.
 5. A fluid control system according to claim 1 wherein said first valve consists of a slide valve having a movable spool, said spool being movable responsive to a predetermined pressure in said second fluid line to urge said first valve in the closed position.
 6. A fluid control system according to claim 1 wherein said first and second valves consist of slide valves having movable spools provided with actuating rods, and including a control lever pivotally connected to the actuating rods of said first and second valves.
 7. A fluid control system according to claim 6 wherein said pivotal connections are spaced along the length of said control lever.
 8. A fluid control system according to claim 1 including a one-way valve disposed in said first fluid line in series between said first valve and said fluid discharge.
 9. A fluid control system according to claim 1 including a fourth fluid line interconnecting said first fluid line between said first valve and said source of fluid under pressure, and said fluid discharge, said fourth fluid line including a normally closed valve operable to open responsive to a predetermined pressure in said first fluid line between said first and second valves.
 10. A fluid control system according to claim 1 including a one-way valve disposed in said first fluid line in series between said first valve and said source of fluid under pressure, and a fourth fluid line interconnecting said first fluid line between said first valve and said one-way valve, and said fluid discharge, said fourth fluid line including a normally closed valve operable to open responsive to a predetermined pressure in said first fluid line between said first and second valves.
 11. A fluid control system according to claim 1 wherein said first and second valves consist of slide valves having movable spools provided with actuating rods, and including a control lever pivotally connected at spaced points along its length to said actuating rods, a one-way valve disposed in said first fluid line in series between said first valve and said source of fluid under pressure, and a fourth fluid line interconnecting said first fluid line between said first valve and said one-way valve, and said fluid discharge, said fourth fluid line including a normally closed valve operable to open responsive to a Predetermined pressure in said first fluid line between said first and second valves.
 12. A fluid control system according to claim 11 wherein said first valve is urged into the closed position responsive to a predetermined pressure in said second fluid line. 